Merge pull request #704 from anmazzotti/forbid_0_control_plane_replicas

Forbid 0 RKE2ControlPlane replicas

Author: anmazzotti

controlplane/api/v1beta1/rke2controlplane_webhook.go

@@ -139,6 +139,7 @@ func (rv *RKE2ControlPlaneCustomValidator) ValidateCreate(_ context.Context, obj
 	allErrs = append(allErrs, rcp.validateCNI()...)
 	allErrs = append(allErrs, rcp.validateRegistrationMethod()...)
 	allErrs = append(allErrs, rcp.validateMachineTemplate()...)
+	allErrs = append(allErrs, rcp.validateSpec()...)
 
 	if len(allErrs) == 0 {
 		return nil, nil
@@ -166,6 +167,7 @@ func (rv *RKE2ControlPlaneCustomValidator) ValidateUpdate(_ context.Context, old
 	allErrs = append(allErrs, bootstrapv1.ValidateRKE2ConfigSpec(newControlplane.Name, &newControlplane.Spec.RKE2ConfigSpec)...)
 	allErrs = append(allErrs, newControlplane.validateCNI()...)
 	allErrs = append(allErrs, newControlplane.validateMachineTemplate()...)
+	allErrs = append(allErrs, newControlplane.validateSpec()...)
 
 	oldSet := oldControlplane.Spec.RegistrationMethod != ""
 	if oldSet && newControlplane.Spec.RegistrationMethod != oldControlplane.Spec.RegistrationMethod {
@@ -279,3 +281,27 @@ func (r *RKE2ControlPlane) validateMachineTemplate() field.ErrorList {
 
 	return allErrs
 }
+
+func (r *RKE2ControlPlane) validateSpec() field.ErrorList {
+	var allErrs field.ErrorList
+
+	if r.Spec.Replicas == nil {
+		allErrs = append(
+			allErrs,
+			field.Required(
+				field.NewPath("spec", "replicas"),
+				"is required",
+			),
+		)
+	} else if *r.Spec.Replicas <= 0 {
+		allErrs = append(
+			allErrs,
+			field.Forbidden(
+				field.NewPath("spec", "replicas"),
+				"cannot be less than or equal to 0",
+			),
+		)
+	}
+
+	return allErrs
+}

controlplane/api/v1beta1/rke2controlplane_webhook_test.go

@@ -0,0 +1,77 @@
+/*
+Copyright 2025 SUSE LLC.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1beta1
+
+import (
+	"context"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/utils/ptr"
+)
+
+var _ = Describe("RKE2ControlPlane webhook", func() {
+	var (
+		oldRcp    *RKE2ControlPlane
+		rcp       *RKE2ControlPlane
+		defaulter = &RKE2ControlPlaneCustomDefaulter{}
+		validator = &RKE2ControlPlaneCustomValidator{}
+	)
+	BeforeEach(func() {
+		rcp = &RKE2ControlPlane{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "test-control-plane",
+				Namespace: "test",
+			},
+			Spec: RKE2ControlPlaneSpec{
+				MachineTemplate: RKE2ControlPlaneMachineTemplate{
+					InfrastructureRef: v1.ObjectReference{
+						Name:      "foo",
+						Namespace: "bar",
+					},
+				},
+			},
+		}
+		oldRcp = rcp.DeepCopy()
+		Expect(defaulter.Default(context.TODO(), rcp)).Should(Succeed())
+		Expect(defaulter.Default(context.TODO(), oldRcp)).Should(Succeed())
+	})
+	It("Should not create RKE2ControlPlane with 0 replicas", func() {
+		rcp.Spec.Replicas = nil
+		_, err := validator.ValidateCreate(context.TODO(), rcp)
+		Expect(err).Should(HaveOccurred())
+		rcp.Spec.Replicas = ptr.To(int32(0))
+		_, err = validator.ValidateCreate(context.TODO(), rcp)
+		Expect(err).Should(HaveOccurred())
+		rcp.Spec.Replicas = ptr.To(int32(1))
+		_, err = validator.ValidateCreate(context.TODO(), rcp)
+		Expect(err).ShouldNot(HaveOccurred())
+	})
+	It("Should not update RKE2ControlPlane with 0 replicas", func() {
+		rcp.Spec.Replicas = nil
+		_, err := validator.ValidateUpdate(context.TODO(), oldRcp, rcp)
+		Expect(err).Should(HaveOccurred())
+		rcp.Spec.Replicas = ptr.To(int32(0))
+		_, err = validator.ValidateUpdate(context.TODO(), oldRcp, rcp)
+		Expect(err).Should(HaveOccurred())
+		rcp.Spec.Replicas = ptr.To(int32(1))
+		_, err = validator.ValidateUpdate(context.TODO(), oldRcp, rcp)
+		Expect(err).ShouldNot(HaveOccurred())
+	})
+})